The immune system in cancer patients is often suppressed and attempts to apply immunotherapy are met with failure. We are proposing here to develop a new approach of experimental immunotherapy for cancer patients which is based on the idiotype network concept. According to this hypothesis, certain idiotopes mimick antigens (internal antigens), including self and tumor-associated antigens. Since we have recently used this concept to produce an experimental idiotope vaccines against streptococcal infection in mice, we will apply the same strategy to produce idiotope vaccines for cancer patients. Vaccination against streptococcal pneumonia is required in therapeutic protocols for lymphoproliferative malignancies; however existing vaccines (Pneumovax) often is ineffective. We propose to develop a substitute for this vaccine based on our experience with the anti-steptococcal idiotype vaccines in mice. We are also planning to develop an idiotope vaccine against human B cell lymphomas. This approach is based on our ability to produce specific hybridoma antibodies against lymphoproliferative malignancies which provide the necessary tools to generate anti-idiotypes expressing the internal antigens of such tumors. Finally, we will improve the compatibility and the effectiveness of murine-based idiotype vaccines by creating chiemiric mouse-man anti-idiotype antibodies using molecular biology methods.